(Updates with polls open)
By Marty Graham
SAN DIEGO, Feb 11 (Reuters) - In a race seen as too close to call, San Diego voters went to the polls on Tuesday to choose one of two city councilmen to succeed former Mayor Bob Filner, who resigned last summer amid multiple allegations of sexual harassment.
The runoff between the two top vote-getters in a special election last fall pits Republican Kevin Faulconer, backed by the city's downtown establishment, against Democrat David Alvarez, seeking to become the city's first Hispanic mayor.
The winner will succeed the disgraced former mayor who resigned at the end of August after a string of women, starting with his then-press secretary Irene McCormack Jackson, came forward with allegations of harassment.
McCormack Jackson was first of nearly 20 women to publicly accuse Filner of making unwanted sexual advances and other inappropriate behavior during his brief tenure as mayor of California's second-largest city.
Michael Vu, spokesman for the San Diego County Registrar of Voters, said 45 percent to 50 percent of the county's registered voters were expected to cast their ballots. Vu said the registrar's office had already received some 170,000 mail-in ballots.
Faulconer, the front-runner in a field of 11 candidates who ran in November, holds a scant 1 percentage point lead over Alvarez, according to a Survey USA poll commissioned by local news outlets UTSanDiego.com and 10News.com.
According to that survey on the eve of Tuesday's runoff, 47 percent of voters favor Faulconer and 46 percent support Alvarez, with 7 percent undecided.
To supporters, Faulconer represents the center-right that was long the political pedigree of mayors in California's second-most populous city, which has traditionally tended to lean conservative, in part because of its large military and retired military presence.
The 2012 election of Filner, a 10-term U.S. congressman who became San Diego's first Democratic mayor, was considered a political turning point.
APOLOGY, TREATMENT NOT ENOUGH
But Filner's career could not withstand the political and public outcry against him as harassment allegations streamed in, even after he apologized for his behavior and sought psychiatric treatment. He later pleaded guilty to criminal charges of false imprisonment and battery involving three women and was sentenced to three months of home confinement.
On Monday, municipal officials announced that the city and Filner had agreed to a $250,000 compensation package to settle the sexual harassment suit brought by McCormack Jackson, with the entire sum coming from city coffers.
Alvarez, whose platform most resembles Filner's, was elected to the city council in 2010 by largely working-class and Hispanic neighborhoods, including San Ysidro and Barrio Logan, where he grew up. He has established a track record of fighting for those communities, often finding himself at odds with downtown interests.
Support from San Diego's Latino neighborhoods, long ignored by the city's mainstream politicians, was seen as key in elevating Filner, who ran on a progressive platform.
Now Alvarez has a clear shot at becoming San Diego's first Hispanic elected mayor - at least since California statehood - in a city originally founded as a presidio, or military post, by the Spanish five decades before Mexican independence.
The race between Faulconer and Alvarez turned nasty in the final days of the campaign, with stacks of mailers alleging that Alvarez is a tool of the unions and, at age 33, too young to run America's sixth-largest city.
Other mailers point out that Faulconer is a member of the San Diego Yacht Club, voted to cut death and disability benefits for firefighters, and charge that he is a pawn of downtown business interests.
The special election and run-off are expected to cost the city more than $7 million, according to county Registrar of Voters Bonnie Stone. Many of the ballots are being returned by mail, which may further slow the vote-counting process, she said. (Reporting by Marty Graham; Editing by Steve Gorman, Ken Wills and Gunna Dickson)